<template>
  <div class="tag-select">
    <tag-select-option @click="toggleCheck">全部</tag-select-option>
    <slot></slot>
    <a @click="toggle" v-show="showTrigger" ref="trigger" class="trigger">
      展开
      <a-icon style="margin-left: 5px" :type="collapsed ? 'down' : 'up'" />
    </a>
  </div>
</template>

<script>
  import TagSelectOption from './TagSelectOption'
  export default {
    name: 'TagSelect',
    Option: TagSelectOption,
    components: { TagSelectOption },
    data() {
      return {
        showTrigger: false,
        collapsed: true,
        screenWidth: document.body.clientWidth,
        checkAll: false,
      }
    },
    watch: {
      screenWidth: function () {
        this.showTrigger = this.needTrigger()
      },
      collapsed: function (val) {
        this.$el.style.maxHeight = val ? '39px' : '78px'
      },
    },
    mounted() {
      let _this = this
      // 此处延迟执行，是为解决mouted未完全完成情况下引发的trigger显示bug
      setTimeout(() => {
        _this.showTrigger = _this.needTrigger()
        _this.$refs.trigger.style.display = _this.showTrigger
          ? 'inline'
          : 'none'
      }, 1)
      window.onresize = () => {
        return (() => {
          window.screenWidth = document.body.clientWidth
          _this.screenWidth = window.screenWidth
        })()
      }
    },
    methods: {
      needTrigger() {
        return (
          this.$el.clientHeight < this.$el.scrollHeight ||
          this.$el.scrollHeight > 39
        )
      },
      toggle() {
        this.collapsed = !this.collapsed
      },
      getAllTags() {
        const tagList = this.$children.filter((item) => {
          return item.isTagSelectOption
        })
        return tagList
      },
      toggleCheck() {
        this.checkAll = !this.checkAll
        const tagList = this.getAllTags()
        tagList.forEach((item) => {
          item.checked = this.checkAll
        })
      },
    },
  }
</script>

<style lang="less" scoped>
  .tag-select {
    position: relative;
    display: inline-block;
    max-height: 39px;
    padding-right: 50px;
    overflow: hidden;
    user-select: none;
  }
  .trigger {
    position: absolute;
    top: 0;
    right: 0;
  }
</style>
